Browsing by Author "Serwanga, Jennifer"

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    Association between serotonin transporter gene polymorphisms and increased suicidal risk among HIV positive patients in Uganda
    (BMC genetics, 2017) Kalungi, Allan; Seedat, Soraya; Hemmings, Sian M. J.; Merwe, Lize van der; Joloba, Moses L.; Nanteza, Ann; Nakassujja, Noeline; Birabwa, Harriet; Serwanga, Jennifer; Kaleebu, Pontiano; Kinyanda, Eugene
    Persons living with HIV/AIDS (PLWHA) are at an increased risk of suicide. Increased suicidal risk is a predictor of future attempted and completed suicides and has been associated with poor quality of life and poor adherence with antiretroviral therapy. Clinical risk factors have low predictive value for suicide, hence the interest in potential neurobiological correlates and specific heritable markers of suicide vulnerability. The serotonin transporter gene has previously been implicated in the aetiology of increased suicidal risk in non-HIV infected study populations and its variations may provide a platform for identifying genetic risk for suicidality among PLWHA. The present cross-sectional study aimed at identifying two common genetic variants of the serotonin transporter gene and their association with increased suicidal risk among human immunodeficiency virus (HIV)-positive adults in Uganda. Results: The prevalence of increased suicidal risk (defined as moderate to high risk suicidality on the suicidality module of the Mini Neuropsychiatric Interview (M.I.N.I) was 3.3% (95% CI, 2.0–5.3). The 5-HTTLPR was found to be associated with increased suicidal risk before Bonferroni correction (p-value = 0.0174). A protective effect on increased suicidal risk was found for the 5-HTTLPR/rs25531 SA allele (p-value = 0.0046)- which directs reduced expression of the serotonin transporter gene (5-HTT). Conclusion: The SA allele at the 5-HTTLPR/rs25531 locus is associated with increased suicidal risk among Ugandan PLWHA. Further studies are needed to validate this finding in Ugandan and other sub-Saharan samples.
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    HIV-1 superinfection can occur in the presence of broadly neutralizing antibodies
    (Vaccine, 2018) Serwanga, Jennifer; Ssemwanga, Deogratius; Muganga, Michael; Nakiboneka, Ritah; Nakubulwa, Susan; Kiwuwa-Muyingo, Sylvia; Morris, Lynn; Redd, Andrew D.; Quinn, Thomas C.; Kaleebu, Pontiano
    Superinfection of individuals already infected with HIV-1 suggests that pre-existing immune responses may not adequately protect against re-infection. We assessed high-risk female sex workers initially infected with HIV-1 clades A, D or A/D recombinants, to determine if HIV-1 broadly neutralizing antibodies were lacking prior to superinfection. Methods: Six superinfected female sex workers previously stratified by HIV-1 high-risk behavior, infecting virus clade and volunteer CD4 counts were evaluated at baseline (n = 5) and at 350 days post-superinfection (n = 6); one superinfected volunteer lacked pre-superinfection plasma. Retrospective plasmas were assessed for neutralization of a multi-clade panel of 12 HIV-1 viruses before superinfection, and then at quarterly intervals thereafter. Similarly stratified singly infected female sex workers were correspondingly assessed at baseline (n = 19) and 350 days after superinfection (n = 24). Neutralization of at least 50% of the 12 viruses (broad neutralization), and geometric means of the neutralization titers (IC50) were compared before and after superinfection; and were correlated with the volunteer HIV-1 superinfection status, CD4 counts, and pseudovirus clade. Results: Preexisting broad neutralization occurred in 80% (4/5) of the superinfected subjects with no further broadening by 350 days after superinfection. In one of the five subjects, HIV-1 superinfection occurred when broad neutralization was lacking; with subsequent broadening of neutralizing antibodies occuring within 9 months and plateauing by 30 months after detection of superinfection. Clade B and C pseudoviruses were more sensitive to neutralization (13; [87%]); and (12; [80%]) than the locally circulating clades A (10; [67%]) and D (6; [40%]), respectively (p = 0.025). Low antibody titers correlated with clade D viruses and with >500 CD4 T cell counts, but not with the superinfection status. Conclusion: These data demonstrate that HIV-1 superinfection can occur both in the presence, and in the absence of broadly neutralizing antibodies.
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    Impaired HIV-specific T-cell responses in HIV and S. mansoni coinfected Ugandans
    (bioRxiv, 2022) Obuku, Andrew Ekii; Rukundo, Anjellina; Odong, Matthew; Auma, Betty; Serwanga, Jennifer; Nkangi, Ronald; Okello, Joseph; Nakitto, Zahara; Joloba, Moses; Kaleebu, Pontiano; Sekaly, Rafik
    Fishing communities surrounding Lake Victoria in Uganda show an HIV-1 prevalence of 28% and incidence rates of 5%. More than 50% of the fishermen on the shores of Lake Victoria are infected with S. mansoni. Fishermen are more likely to die of AIDS related illness than farmers in the Lake Victoria region. Using polychromatic flow cytometry and mesoscale discovery platform, HIV specific and non-specific responses were measured and compared within individuals when HIV and S. mansoni coinfected and after the S. mansoni was cleared. Sixty-two unique clusters of cells in the UMAP space were identified after stimulations with GAG PTE POOL-1 and GAG PTE POOL-2 independently. However, the frequency of only three clusters is significantly higher after S. mansoni clearance. In addition, S. mansoni infection is associated with higher IL-9 and IL-10 and lower IL-15 in HIV and S. mansoni coinfected individuals. IL-9 concentration at enrolment visit predicts CD4 decline. S. mansoni infection negatively affects HIV specific and non-specific immune responses in HIV and S. mansoni coinfected individuals.
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    Profile of T Cell Recognition of HIV Type 1 Consensus Group M Gag and Nef Peptides in a Clade A1- and D-Infected Ugandan Population
    (AIDS research and human retroviruses, 2012) Serwanga, Jennifer; Mugaba, Susan; Pimego, Edward; Nanteza, Bridget; Lyagoba, Fred; Nakubulwa, Susan; Heath, Laura; Nsubuga, Rebecca N.; Ndembi, Nicaise; Gotch, Frances; Kaleebu, Pontiano
    Reagents for evaluating non-clade B HIV-specific T cell responses are uncommon. Peptides based on highly conserved HIV-1 consensus group M sequences that are phylogenetically closer to most circulating strains may provide potential alternative reagents in populations with diverse infections, and may be relevant for vaccine design. Recognition of such reagents in clade A1-and D-infected populations has not been previously evaluated. Interferon (IFN)-c ELISpot assay was used to evaluate T cell recognition of Gag and Nef peptides based on consensus group M sequences in 50 treatment-naive adults predominantly infected with HIV-1 clades A1 and D. Gag-induced T cell responses were correlated with gag sequence diversity. Infecting clades were determined from gag sequences for 45 of the 50 subjects as 40% clade A1 (18/45), 45% clade D (20/45), 2% clade C (1/45), 2% A1/C recombinant (1/45), 2% A1/D (1/45), 7% CRF10_CD (3/45), and 2% U (unclassifiable) (1/45). The mean genetic divergence and diversity of clade A and D gag region compared to group M consensus sequences at synonymous and nonsynonymous nucleotide and amino acid levels were not always significant. Gag peptides were targeted at significantly higher frequency [88% (44/50)] than Nef [64% (32/50)]; p = 0.014, although their mean IFN-c magnitudes were comparable ([3703 (95% CI 2567–4839)] vs. [2120 (95% CI 478–3762)]), respectively. Measurable virus-induced IFN-c responses were detected in 96% (48/50) individuals, primarily targeting the more conserved Gag p24 and Nef central core regions. Use of these reagents to screen for HIV-specific IFN-c responses may mitigate the challenge of viral diversity; although this targeting is apparently biased toward a few highly conserved epitopes.